Process for improving the color of surface-active agents



Patented Aug. 17, 1948 PROCESS FOR IMPROVING THE COLOR SURFACE-ACTIVE AGENTS Leland James Beckham, Geddes, and William Alfred Fessler, Camilius, N. Y., assignorsto Allied Chemical & Dye Corporation, a corporatlon of New York No Drawing. Application October 12, 1943, Serial N0. 505,960

This invention relates to an improvement in certain processes for preparing water-soluble surface-active compositions which are suitable for use as detergents, wetting agents, emulsifying agents, dispersing agents, washing agents or cleansing agents, from olefinic hydrocarbon mixtures, especially those obtained from petroleum and other mineral sources.

As disclosed in United States Patent No. 2,265,993 of December 16, 1941, surface-active compositions can be advantageously obtained from hydrocarbon mixtures containing olefinic hydrocarbons having or more carbon atoms, by treatment of such mixtures with a nitrosyl halide to convert the oleflns into their nitrosyl halide addition products, followed by reaction of the addition products with an aqueous sulflte to convert the addition products into a complex mixture of surface-active hydrocarbon derivatives containing water-solubilizing groups, especially sulfonate and sulfamate groups. The products of this process comprise mixtures of sulfonated ketones, sulfonated amines, sulfonated alkylidene sulfamates, "sulfonated alkyl sulfamates, and bisulfite addition products of sulfonated alkylidene sulfamates.

' Application, Serial No. 427,345, filed January 19, 1942, of Herman A. Beekhuis, Jr., discloses a modification of the process of the aforesaid patent in which nitrosyl chloride containing nitrogen tetroxide or nitrogen trioxide is employed in the initial treatment of the oleiinic hydrocarbon mixtures.

U. S. P. 2,313,719 of March 16, 1943, to one of us discloses another process for making similar surface-active compositions from the oleflnic hy-= drocarbonmixtures, in which the oleflnic hydrocarbon mixtures are reacted-with nitrogen tetroxide or' nitrogen trioxide to convert the oleflnic hydrocarbons contained in the mixtures to nitroso '1 Claims. (Cl. 200-504) to the nitrosation-sulfitation process of the aforesaid patents and application; so that when such oleflnic hydrocarbon mixtures, and especially cracked or dehydrogenated petroleum fractions, are subjected to a nitrosation-sulfltation process,-

detergent generally meets with considerable sale" In carry--- resistance because of its appearance. ing out the process of U. S. P. 2,265,993, it has been observed, furthermore, that considerable variation in the depth of color of the surfaceactive compositions results upon subjecting ole-. finic hydrocarbon mixtures from various sources.

to the nitrosation-sulfitation treatment. It has been found for instance that marked differences exist in the content of chromogenetic substances We have now discovered that the color of sur-' face-active compositions prepared in the aforesaid manner, particularly by processes involving nitrates or nitroso nitrites, and the addition products obtained are reacted with an aqueous sulflte.

It has been found that olefinic hydrocarbon mixtures of the'aforesaid type contain chromogenetic, or color-forming, constituents which,'re-

gardless whether they are colorless or colored in themselves, form colored bodies when subjected nitrosation with nitrosyl chloride, from hydrocarbon mixtures comprising olefins and derived from a mineral source, can be reduced to a small fraction of its normal value (in terms of relative light-absorbing power) by subjecting the olefinic hydrocarbon mixture which serves as the raw material-for the nitrosation-sulfitation process to extraction, before treatment thereof with the nitrosating agent, with an incompletely miscible polar solvent of the type hereinafter identified. Moreover, we have found that the aforesaid improvement in color of the surf ace-active compositions can be achieved, without removing morethan a minor portion of the unsaturated constituents ofthe original hydrocarbon mixture, by carrying out the extraction with a limited amount of said solvent; for example, an amount not ex-- ceeding that which would reduce the proportion of olefinic constituents in the rafiinate, in terms of molecular equivalents of mono-oleflns, to per cent of the proportion of oleflnic constituents,

in terms of molecular equivalents of monoconstituents which form insoluble gum during the nitrosation.

We havefurther found that furfural, ethylene glycol monomethyl ether, and liquid sulfur dioxide have exceptional extractive powers for the chromogenetic constituents of such mixtures and especially those composed mainly of hydrocarbons containing 14 to-23 carbon atoms, as hereinafter more fully described.

It was well known heretofore to extract petroleum fractions with selective solvents of various types including the aforesaid polar solvents, for the purpose'of increasing their resistance to oxidation, to increase their viscosity or lubricating value, or to remove colored impurities. -It was generally recognized that such extraction treatments were effective for removal of at least part of the unsaturated constituents and cyclic (e. g.,

'naphthenic or aromatic) constituents of complex hydrocarbon mixtures, leaving the parafllnic constituents in a more concentrated form in the residue or rafllnate phase.

It was not known, however, that the chromogenetic constituents are selectively dissolved by polar solvents of the type referred to herein. The nature of the chromogenetic constituents of the hydrocarbon mixtures serving as raw materials for the aforesaid nitrosation-sulfitation processes is not known. Furthermore, it was not known that chromogenetic constituents could be extracted by said solvents without substantially altering the degree of unsaturation of the hydrocarbon mixtures, in the case of such oleflnic hydrocarbon mixtures as petroleum fractions obtained by cracking processes. It was therefore surprising to find that the preliminary extraction of the hydrocarbon mixture in accordance with. the present invention would so modify the 1 hydrocarbon mixture that nitrosation-suiiltation products of greatly improved color could be obtained without interfering with the operation of the nitrosation-sulfitation process. Moreover, the amount of surface-active agents, obtained per unit weight of olefinic hydrocarbons contained in the hydrocarbon mixture subjected to nitrosation and sulfitation, is in most cases increased substantially by the preliminary solvent extraction according to this invention, often by as much as 10% to 15%.

The process according to this invention comprises extracting a hydrocarbon mixture containing oleflnic hydrocarbons and derived from a mineral source, with a polar solvent which is incompletely miscible therewith and which is characterized by preferential dissolving power for the more polar constituents of cracked petroleum, by bringing the solvent and the hydrocarbon mixture into intimate contact, separating the solvent extract phase from the undissolved hydrocarbon or rafiinate phase, and reacting the olefins contained in the raflinate phase successively with a nitrosating agent of the type disclosed in the patents and application discussed above, but preferably with a nitrosyl halide, and then with an aqueous solution of a water-soluble sulfite. Preferably any residual solvent dissolved in the rafllnate phase is eliminated from the resultant hydrocarbon mixture, before treatment thereof with the nitrosating agent, and any insoluble gum formed during the nitrosation treatment is preferably separated from the resulting reaction mixture before treatment thereof with the aqueous solution of the water-soluble sulflte.

If desired, in order to insure utmost utilization of the oleflnic components of the original hydrocarbon mixture, the portion thereof which is removed by extraction and contained in the solvent extract phase, including the chromogenetic constituents, can be processed in the same manner as the purified portion contained in the raflinate phase, for example by subjecting it to a nitrosation-suifltation treatment. While the resulting nitrosation-sulfitation products are highly colored, they possess valuable surface-active properties in aqueous solution, such as wetting, emulsifying and cleansing power; so that they can be used to advantage where these properties are desired but where the color of the composition is of no consequence.

The improved process of this invention can be advantageously applied generally to olefin-containing hydrocarbon mixtures derived from mineral sources; for instance, petroleum hydrocarbons obtained by cracking, dehydrogenating or oxidizing petroleum fractions, and synthetic hydrocarbon mixtures obtained by catalytic hydrogenation of carbon oxides or by catalytic hydrogenation of coal. The process is especially advantageous for treatment of such hydrocarbon mixtures obtained by cracking or dehydrogenating petroleum fractions. In order to form surface-active compositions the oleilns contained in such mixtures generally contain 10 to 30 carbon atoms. However, the present process is preferably applied to oleilnic hydrocarbon mixtures composed mainly of hydrocarbons containing 14 to 23 carbon atoms, 1. e., containing not more than 15% by weight of hydrocarbons having more than 23 or less than 14 carbon atoms. The best results, in so far as improvement in color of the surface-active agents and convenience and economy of operation are concerned, are obtained with hydrocarbon mixtures containing no substantial proportion (not more than 15% by weight) of hydrocarbons other than those having 14 to 23 carbon atoms. Such mixtures have been found to yield not only the most effective surface-active materials but also to respond most readily to the improved treatment of this invention. The presence of excessive proportions of hydrocarbons of less than 14 carbon atoms in the hydrocarbon mixture to be extracted tends to cause dilution of the selective solvent employed in the extraction, rendering it less selective for removal of chromogenetic materials and rendering recovery of the solvent by distillation of the extract difllcult; while the presence of excessive amounts of hydrocarbons of more than 23 carbon atoms tends to increase inordinately the amount of solvent required to effect a, given improvement in the color of the surface-active agents produced. The selective solvents employed according to this invention are polar compounds, containing nitrogen, oxygen or sulfur, which are partly miscible with the hydrocarbon mixture to be treated, and which are characterized by preferential dissolving power for the more polar constituents of cracked petroleum-that is, they have greater dissolving power for the more-polar and polarizable constituents of cracked petror extraction.

leum' (such as, compounds containing oxygen, sulfur or nitrogen, aromatic hydrocarbons, and conjugated dioleflns) than for the less polar and polarizable constituents (such as, parafllns and cycloparailins). The preferred solvents are chosen on the basis of their selectivity in extracting the chromogenetic constituents of the oleflnic hydrocarbon'mixtures to be processed.

By way of contrast with the extraction processes 4 heretofore known, inthe extraction treatment of this invention, the purpose is to; avoid, as far as possible, the removal of the unsaturated .con-

stituents of the original hydrocarbon mixture,

' while eliminating the chromogenetic constitu-- tivity for the chromogenetic constituents of oleflnic hydrocarbon mixtures containing mainly 'hydrocarbons from 14 to 23 carbon atoms.

' constituents of the hydrocarbon'mixtures. and

from the boiling range of the hydrocarbons contained in the rafilnate and also in the solvent extract, being for instance less than 200 C.,.in

order to facilitate solvent recovery by distillation.

A considerable number of solvents have been found suitable for removing chromogenetic. constituents from hydrocarbon mixtures according to this invention, especially where oleflnic hydrocarbon mixtures in which the hydrocarbons contain from 14 to '23 carbon atoms are used as raw materials. They include esters (such as methyl lactate and methyl formate), alcohols (such as, diethylene glycol, furfuryl alcohol, ethanolamine, diethanolamine, or ethylene chlorohydrin)"; ethers (such as beta-beta-dichlordiethyl ether and ethylene glycol monomethyl ether), aldehydes (such as furfural) hydroxy aromatic compounds(such as phenol or cresol), nitro compounds (such as nitro-methane' or nitro-benzene), cyclic nitrogen bases (such as morpholine or pyridine), alkylar'nines (such as methylamine orethylene diamine), and liquid sulfur dioxide. Sulfur dioxide is suitable, for instance at 50 C. for treatment of oleflnic petroleum fractions, the operation being carried out at this temperature under superatmospheric pressure. Methyl lactate, ethylene chlorohydrin, and nitro-methane can be used at temperatures from to 100 C. However, ethylene chlorohydrin tends to corrode metal equipment; nitro-methane is explosive at elevated temperatures; and methyl lactate tends to decompose with formation of lactides durin distillation for its recovery. Solvents such as solubility of hydrocarbons therein, e. g., by maintaining relatively low temperatures or by introducingminor proportions of antisolvents inv the Morphollne, pyridine and methyl formate can be used at temperatures below 30 C.

. or in the presence of an antisolvent.

We have found that furfural, ethyleneglycol .monomethyl ether (methyl Cellosolve), and liquid sulfur dioxide are preferable for the purposes of the present invention from the standpoint of specific gravity,- boiling point, stability.- and selec its lower cost; and to liquid sulfur dioxide because of. the necessity of using a closed system under pressure, at optimum operating temperatures in order to maintain the sulfur dioxide in the liquid phase. Preferably, dry (i. e., substantially free of moisture) furfural and ethylene glycol monomethyl ether are used, since the presence of moisture reduces the dissolving power of the solvents for constituents of the hydrocarbon mixture, and in the ease of furfural tends to lower its selectivity in removing chromogeneticmaterials.

Thus, if moisture is present in substantial amount.

in either of these solvents, it increases the amount of solvent required to efl'ect a given degree of purification, and in the case of furfural correspondingly lowers the yield of purified material of a given degree of purity.

The relative quantities of the solvent and of the oleflnic hydrocarbon mixture introduced into the extraction zone, the temperature of the extraction and the intimacy and duration of contact of the liquids in the extraction zone areregulated so that only a part of the unsaturated, or more specifically the oleflnic, constituents of the original hydrocarbon mixture are removed in the form of a solvent-extract. The quantity of the solvent employed in the extraction is preferably limited to an amount yielding a rafllnate in which the hydrocarbons contain a proportion of olefinic solved in the railinate is then removed, e. g., by

distillation, especially under reduced pressure, or by extraction with another solvent in which the hydrocarbons are insoluble.

The raflinate is then-processed to produce a nitrosation-sulfitation product, preferably in the' manner described in U. S. P. 2,265,993, by reaction with a nitrosyl halide and subsequent suifitation of. the nitrosation product with an aqueous suliite solution, or if desired, the process" of U. S.- P. 2,313,719 or U. S. patent application Serial No. 427,345 of January 19., 1942. The unreacted hydrocarbons are removed from the sulfitation mixture and the latter is evaporated to dryness to obtain water-soluble surface-active materials in" theform of a composition suitable for marketng.

When ethylene glycol monomethyl ether or furfural is used as the extractionsolvent, it has been found advantageous to employ a countercurrent extraction column equivalent to -7 to 15, and preferably about 10, theoretical 'plates. The hydrocarbon mixture or 'rafiinate preferably forms the continuous phase, and the solvent or extract, the discontinuous phase. The temperature can be maintained at 0 to 70 0., and preferably at 25.. to 50C., during the extraction; optimum results are obtained, however, at temperatures of 25 to 30 C. The relative rates of introduction of the solvent and of the hydrocarbon mixture can be adjusted within the range of about 2.5:1 to about :1, and pre er bl about 3:1. Lower ratios of the rate of flow of solvent to hydrocarbon mixture, for instance as low as 0.5:1 by weight, have been found to improve the color of the detergent compositions to a considerable extent, however.

Liquid sulfur dioxide can be employed in a similar manner in a closed apparatus under superatmospheric pressure, for example, at about 50 to 52 lbs. per square inch gauge pressure, at a temperature of about 30 C. or at 105 lbs. per square inch gauge pressure at a temperature of about 50 C.

After extraction is complete, the ratiinate is usually treated for removal of the residual polar solvent contained therein; for instance, by distillation or by extraction with another solvent (e. g., water) which is substantially immiscible with the hydrocarbons but is to some extent a solvent for the extracting agent. The solvent may be similarly recovered i'rom the solvent extract and recycled to the extraction process.

The rafiinate fraction, containing the major portion of the olefins present in the original hydrocarbon mixture but from which chromogenetic materials have been removed, is subjected to treatment with a nitrosating agent, preferably a nitrosyl halide, and especially nitrosyl chloride, in order to convert the olefins contained therein into nitrosation products, especially their nitrosyl halide addition products. The temperature can be maintained from -20 C. to 80 C.,' but is preferably held at not more than 35 C. From about 1.25 to 4,"and preferably 2.5 to 3, mols of nitrosyl chloride are employed per mol equivalent of mono-olefin in the hydrocarbon mixture. After removing excess nitrosyl chloride by aeration, the mixture is allowed to settle and the liquid portion thereof preferably decanted from the insoluble gummy substance formed during the nitrosyl halide treatment.

The decanted reaction mixture is then sulfitated by heating to a temperature of about 85 C. with an aqueous alkali metal sulfite solution (e. g., about 2.5 to 5 mols and preferably 4 mols for each mol of original mono-olefln) containing a water-soluble organic solvent, e. g., isopropyl alcohol (from 1 to 15 mols and preferably about 3 mols per mol of mono-olefin equivalent). The reaction requires about 4 to about 16 hours, depending upon the concentration of the nitrosyl halide addition products in the hydrocarbon mixture, lower concentrations requiring a longer reaction period. When the reaction is complete the unreacted oil is removed by decantation and the portion emulsifled'in the aqueous part of the reaction mixture is removed, for instance, by extraction with a low-boiling hydrocarbon fraction, such as petroleum naphtha or heptane, in the presence of a minor proportion of isopropyl alcohol. The aqueous solution is separated from the unreacted hydrocarbons by stratiflcation and decantation, and the isopropyl alcohol removed from the solution by distillation. The organic carbon content of the solution is advantageously standardized by addition of inorganic salts, such as sodium sulfate or sodium sulfite, and the solutionis evaporated to dryness in order to obtain the surface-active composition in dry form.

Upon determining the light-absorbing power or depth of color of an aqueous solution or the product, for instance by means of a comparative photometer, the light absorption is generally about $4 to about 1 6 of that shown by a product pre- 8 pared from the same petroleum stock but without the preliminary solvent extraction of the present invention.

The hydrocarbon fraction contained in the solvent extract phase, including the chromogenetic components of the original hydrocarbon mixture, preferably after removal of the solvent, can be converted into sulfonate mixtures; for example in the same manner as the rafiinate fraction, or by direct sulfonation as disclosed for instance in U. S. P. 2,179,174. Mixtures of water-soluble sulfonates can be obtained in this -manner which are relatively highly colored .but which nevertheless possess surface-active properties in aqueous solution. In this way, utmost utilization of the olefinic components of the original hydrocarbon mixture can be secured.

The process of this invention is illustrated by the following examples in which temperatures are in degrees centigrade and parts and percentages are by weight.

Example 1.-The following hydrocarbon mixtures were each extracted in a countercurrent extraction zone substantially equivalent to 10 theoretical plates at a temperature of 25 to 30 with furfural, the amounts of the furfural and or the hydrocarbon mixture introduced into the reaction zone being in the ratio of 3:1 (by weight):

A. A cracked petrolatum fraction composed mainly of hydrocarbons containing-from 14 to 23 carbon atoms (with 7.2% of higher molecular hydrocarbons) the average carbon content of the olefins contained therein being 17.4 carbon atoms per molecule, and the mixture including the molecular equivalent of 68.5% of mono-olefins.

' B. A cracked Pennsylvania cylinder stock fraction, composed mainly of hydrocarbons containing 14 to 23 carbon atoms gwith 9.6% of higher molecular weight hydrocarbons) the average carbon content of the oleflns contained therein being 17.7 carbon atoms per molecule, and the mixture including the molecular equivalent of 49.6% of -mo'no-oleflns.

C. A dehydrogenated mineral seal oil fraction, composed of hydrocarbons containing from 14 to 21 carbon atoms, the average carbon content of the olefins contained therein being 17.0 carbon atoms per molecule, and the mixture including the molecular equivalent of 11% of mono-oleflns.

D. A dehydrogenated Pennsylvania gas oil fraction, composed mainly of hydrocarbons of 14 to 23 carbon atoms (with 3.5% of higher molecular weight hydrocarbons) the average carbon content of the olefins contained therein being 18.2 carbon atoms per molecule, and the mixture including the molecular equivalent of 11% of mono-olefins.

E A fraction of a cracked topped Louisiana crude petroleum, composed mainly of hydrocarbons having from 14 to 23 carbon atoms (with about, 13.3% of higher molecular weight hydrocarbons), the average carbon content of the olefins contained therein being 18 carbon atoms per molecule and the mixture including the molecular equivalent of 13.3% of mono-olefins.

F. A fraction of a, cracked topped Louisiana crude petroleum, similar to fraction E, but composed of hydrocarbons containing from 14 to 23 carbon atoms and containing no substantial percentage of hydrocarbons of more than 23 carbon atoms, the average carbon content of the olefins contained therein being 17.7 carbon atoms per molecule, and the mixture including the molecular equivalent of 14.1% of mono-olefins.

G. A fraction of a cracked Louisiana paraflln 9 distillate, composed of hydrocarbons containin 14 to 23 carbon atoms (with about 4.4% of higher including the molecular equivalent of 21.0% of The diiference in density of the two liquid phases was utilized to maintain countercurrent flow in the extraction zone, and to eflect separate recovery of a solvent extract phase and a rafiln-ate phase. The furfural contained in the railinate phase recovered from each of the mixtures was removed by distillation and the equivalent olefin content of the residual rafilnate wa determined. The percentage of each of the hydrocarbon fractions recovered in the form of a rafllnate, and the percentage of the mono-olefin equivalents originally contained in each of the fractions, recovered In order to prepare the nitrosyl chloride addition products of the olefins, quantities of each of the rafiinate mixtures, as well as of the original hydrocarbon mixtures, containing in each case the substantial equivalent of one mol of monoolefin, were gradually mixed with 165 to 195 parts of liquid nitrosyl chloride (2.5 to 3 mols) and the mixtures were agitated and cooled to maintain the temperature below 35. The time for completion of the addition reaction varied from about 5 to about 9 hours. Upon completion of the reaction, the reaction mixture were aerated to remove unreacted nitrosyl chloride, and the insol- .uble gum which was formed by the reaction was allowed to settle. The liquid portion of each reaction mixture was decanted and the amount of insoluble gum determined. The initial quantities of the hydrocarbon mixtures and of the rafflnate mixtures and the quantity of gum formed in each case were as follows:

vessel with an aqueous solution containing a mixture of sodium bisulfite and sodium sulfite in a molar ratio of 1:5, prepared by dissolving 416 parts (4 mols) of sodium bisulfite (NaHSOa) and 177 parts (1.67 mols) of sodium carbonate in 1260 parts (70 mols) of water and 180 parts (3 mols) of isopropyl alcohol. The mixtures were agitated and boiled under reflux at a temperature. f about 10 86 for about 4 hours in the case of the nitrosation mixtures identified as A and B, and about '16 hours in the case of the other nitrosation mixtures (because of the relatively low concentration of the olefin addition products in the latter nitrosation mixtures). The sulfitation reaction mixtures were cooled and allowed to separate into an oily layer comprising mainly unrea-cted hydrocarbons, and an aqueous layer containing surface-active sulfitation products together with a minor proportion of the hydrocarbon fraction,

' emulsified and dissolved therein. The aqueous layers were separated from the hydrocarbon layers and the pH of the former was adjusted to 7.5

to 8.5 by addition of concentrated aqueous caustic The emulsified hydrocarbons were removedby extraction of the aqueous emulsions at to 50 with -a. heptane fraction of petroleum in an amount equal to about twice the volume of aqueous emulsion "to'be extracted. Isopropyl alcohol was removed from the extracted aqueous solutions by distillation. The composition of the aqueous solutions was adLiu-sted by addition of suitable quantities of sodium sulfate'or sodium sulfite, to yield on evaporation to dryness, a mixture containing 17.5% carbon in the form of organic compounds, and the solutions were then evaporated to dryness on a drum drier, e. -g., at about 100 at atmospheric pressure.

In order to determine the effect of the extrac- I tion, the color, 1. e., the relative depth of color.

of each .of the compositions, was determined as of known concentrations were prepared. A layer I of predetermined thickness of the test -sample solution was matched, by visual observation of light transmitted from a given source, against corre- 1 spondinglayers of the series of standard detergent solutions. The reciprocal of the ratio of the concentration of the test sample solution to that of the matching standard'sample was taken as the numerical index of relative depth of color of the detergent to be tested. In effect, this numerical index is proportional to the coefficient of light absorption of the detergent tested, or its relative light absorptive power in units of a scale on which the sulfonate detergent had a'corre Q m D spending light absorption power of -l. The ici- Quantity of Hydrocarbon 3 g; lowing results expressed in units of said scale.

y reaction with reeled N001 $001 were obtained:

Unextracted Unextracted v 1, h L hydrocarbon Bafllnate hydrocarbon Railinate 1550155105151 A orp t i l ol mixture mixture sample pmsample pre- Ratio Hydrocarbon Fraction paged \Yiithiparled :vith Ln P11115356 P1111356 Part5 21 Parts 1 l gry lil'f l l flll li ii' i ue i 500 500 35 2 60 Extraction Extraction 2% 1 1, s 1: 845 11s 6 g: g 81 52 1; 756 930 51 1 2. e 0. as 8: 1,135 1, 310 31 4 2.5 0.45 5.5 12.5 1.5 8.3

1 6.0 0.1 8.6 The decanted liquid portions of the reaction 4.5 0.11 5. mixtures were each introduced into a reaction A comparison of the surface-active properties of the compositions obtained from the original hydrocarbon fractions, and from the corresponding rafiinates in aqueous solution (1. e., the washing and wetting properties), indicated nolsubiii-Ll ma.-

those given in the last column of the preceding table were:

Thus, it was observed that the decrease in color was about A; to about /5 as much as that obtained when 3 parts of furfural were employed in the extraction.

On the other hand, upon increasing the proportion of furfural from 3 to 6 parts for each part of hydrocarbon mixture in the case ofmixtures A, B, C and G, the improvement in color was relatively insignificant. The values for relative depth of color or light absorptive power (in terms of units of the same scale as that employed above) obtained byuse of 6 parts of furfu'ral, and the corresponding values obtained with 3 parts furfural, per part of hydrocarbon mixture in the preliminary extraction step were as follows:

Example 2.--1 part of a cracked petrolatum fraction composed of hydrocarbons containing 14 to 23 carbon atoms and having an average carbon content of 17.5 carbon. atoms per molecule of olefin, said fraction containing the molecular equivalent of '72 per cent of r'nono-olefins, was extra'cted at 30 with successive portions of methyl Cellosolve (i. e., ethylene glycol monomethyl ether) using an equal weight of solvent in the first extraction, and in each of the following extractions, a weight of solvent equal to the weight of the ramnate phase obtained from the preceding extraction. After separating the solvent-extract phase from the raflinate phase in the final extraction step, the methyl Cellosolve 'was removed from the rafllnate by distillation. Equivalent quantities of the original hydrocarbon mixture, and of the rafllnate residue, which consisted of an oleiinic mixture of hydrocarbons containing the molecular equivalent of 71.5% of mono-olefins, were reacted with nitrosyl chloride, employing 2.5 to 3 mols of NOCl per mol equivalent of mono-olefin in the respective hydrocarbo mixtures. The insoluble gum resulting from the nitrosyl chloride treatment was separated fromeach mixture, and the clarified liquid reaction products were heated with aqueous sodium sulfite solutions containing minor proportions of sodium bisulfite and isopropyl alcohol as described in Example 1 employing similar molecular proportions based on v the mol equivalents of mono-olefin originally present. After working up the sulfitation mixtures as described in Example 1, the final products, obtained in a dry form, were tested as in Example 1 for relative light a sorptive power (depth of color). The product obtained from the unextracted hydrocarbon mixture had a light absorptiv power of 2.2, while the product obtained from the rafllnate had a light absorptive power of 0.61, the ratio being 3.6:1. The amount of gum deposited during the nitrosyl chloride treatment of the original hydrocarbon mixture and of the ramnate was in the ratio of 15:1.

Example 3.A surface-active composition was prepared from the cracked petrolatum fraction of Example 2 by a procedure similar to that of Example 2, except that the extraction with methyl Cellosolve was carried out at 50 instead of at 30. The relative amount of gum deposited as a result of the nitrosyl chloride reaction was the same as in Example 2. The depth of color of the product in terms of units of the scale used in the foregoing examples was 0.45 as compared with 0.61 for the product of Example 2. Thus the ratio of the respectiv depth of color values of the products obtained from the unextracted and extracted hydrocarbon mixture wa 4.9:1.

Example 4.1 .part of a cracked petrolatum fraction composed of hydrocarbons containing 14 to 23 carbon atoms and comprising the molecular equivalent of 68.5% of mono-olefins, was extracted at 30 with 10 successive portions of liquid sulfur dioxide in a closed extraction apparatus at a gauge pressure of 50 to 52 lbs. per square inch using an equal weight of the solvent in the first extraction and in each of the following extractions, a weight of solvent equal to the weight of the rafllnate phase obtained from the preceding extraction. After separating the solvent extract phase from the raflinate phase in the finalextraction step, the sulfur dioxide was removed from the rafllnate by distillation. Equivalent quantities of the original hydrocarbon mixture and of the rafiinate residue, which consisted of an olefinic hydrocarbon mixture (d3=0.8l50) containing the molecular equivalent of 62.0% of mono-olefins, were reacted with nitrosyl chloride employing 2.5 to 3 mols of NOCl per mol equivalent of mono-olefin in the respective hydrocarbon mixtures. The insoluble gum resulting from the nitrosyl chloride treatment was separated from each mixture and the clarified liquidreaction products were reacted with aqueous sodium sulfite in the manner described in Example 2. The ratio of the gum deposited in the nitrosyl chloride reaction in the case of unextracted hydrocarbon mixture to that deposited from the raffinate was about :1. The sulfite reaction product obtained from the unextracted hydrocarbon mixture had alight absorptive .power of 4, while the product obtained from the rafllnate had alight absorptive power of 0.5, the ratio being 8:1.

In each of the foregoing examples, the extract phase can be fractionated by distillation to recover the extractant solvent, and the hydrocarbon mixture contained therein can be treated in the same manner as the raflinate fraction with nitrosyl chloride and an aqueous solution of sodium sulfite. Highly colored nitrosation-sulfltation products are obtained in each case possessing valuable surface-active properties. The aforesaid extract can also be converted into valuable surface-active sulfonates by direct sulfonation with sulfuric acid and related sulfonating agents.

It will be realized that numerous variations and modifications of the procedure hereinbefore described and i lustrated can be made without de- 13 parting from the scope of the invention. For example, the nitrosation can be carried out in the presence of an alkali metal carbonate as disclosed in copending application Serial No. 424,944,

filed December 30, 1941, Patent No.2,37l,418, or

in the presence of nitrogen tetroxide or nitrogen trioxide as disclosed in copending a plication Serial No, 427,345, filed January 19, 1942, of H. A. Beekhuis, Jr., Patent No. 2,370,513. Or, if desired, the olefin mixture can be nitrosated with nitrogen tetroxide or nitrogen trioxide or a mixture thereof, as disclosed in U. S. P. 2,313,719. The sulfitation reaction can be carriedcut at temperatures initially below 50 C. and completed at temperatures above 65 according to copending application Serial No. 424,943, filed December 30, 1941, Patent No. 2,343,362. The molecular proportion of blsulfite to normal sulfite employed in the sulfitation reaction is advantageously adjusted to 1:5. in accordance withthe disclosure of copending application Serial No. 424,941, filed December 30, 1941,. Patent No. 2,373,643. The separation of the unpies should be interpreted as illustrative rather reacted hydrocarbons from the aqueous portion of the sulfitation reaction mixture can be facilitated by the use, during the extraction of such hydrocarbons with naphtha, of an emulsion breaker in accordance with the disclosure of copending application Serial No. 427,321, filed January 19, 1942, of W. A. Fesslen. Patent N0. 2,383,120.

The extraction, according to the present invention, can be carried out in any apparatus adapted zone between the extraction solvent and the olefinic hydrocarbon mixture to be extracted, and arranged to effect separation of the solvent extract from the purified "hydrocarbon mixture or rafilnatel It is advantageous to employ an apparatus operating on the countercurrent principle, for instance a packed column in which the solvent and hydrocarbon mixture'are introduced at remote points. and flow in intimate countercurrent contact-finally separating in the form of a solvent-extract phase and a raflinate phase at opposite ends of the apparatus.

It has been proposed heretofore to-carry out the extraction of petroleum oils with selectivesolvents in'such a manner that certain portions of the hydrocarbons dissolved in the extract are liberated, for instance by cooling the extract, the liberated oils being returned to the extraction system. Such modificationsin the extraction according to this invention have been found to improve the yield in some cases, but in general this is accompanied by less efiicient removal of the chromogenetic hydrocarbon constituents so that the surface-active. compositions obtained therefrom are of darker color.

Accordingly, it is preferred to employ a simple countercurrent extraction rather than the aforesaid modification, in order to obtain the desired I improvement in color most economically. For this which accumulates at the top of the tower. The

preferably 14 relative rate of removal of the extract phase is controlled so that the hydrocarbonsolvent interface moves toward the base of the column. Under these conditions, the hydrocarbon mixture constitutes the continuous phase through which.the solvent descends in the form of droplets or as a film on the surface of the packing. The extended surface presented by the packing thus tends to insure intimate contact between the two phases. If desired, two or more extraction towers may be operated in series. For example, the solvent may be admitted at the top of the first tower, while the solvent extract leavingv the base of each tower is pumped to the top of the next tower until finally recovered from the last tower in the series. Meanwhile, the hydrocarbon mixture is introduced into the base of the last tower and the rafflnate issuing from the top of each tower is permitted to flow into the base of the next tower of the series in reverse order until it is recovered from the top of the first tower.

Accordingly, the details of the foregoing examthan in a limiting sense.

'to establish intimate contact in an extraction We claim:

1. In a process for preparing surface-active agents by successively reacting a hydrocarbon mixture containing olefinic hydrocarbons and derived from a mineral source with a nitrosating agent and an aqueous solution of a water-soluble sulfite, the improvement which comprises removing chromogenetic' constituents of an olefin-containing hydrocarbon mixture of the aforesaid type composed mainly of hydrocarbons containing 10 to 30 carbon atoms, by extracting one part by weight of said hydrocarbon mixture with 0.5 to 6 parts by weight of an extracting agent which is incompletely miscible with said hydrocarbon mixture, which has greater dissolving power for the oxygen-containing, sulfur-containing, nitrogen-containing and .aromatic constituents of morpholine, pyridine, methylamine, ethylene diamine and sulfur dioxide, under temperature and pressure conditions at which the extracting agent is inthe liquid phase, separating the solvent-extract phase from the railinate phase, and reacting olefins contained in the raffinate phase with the nitrosating agent. I

2. In a process for preparing surface-active agents by successively reacting a hydrocarbon mixture'containing olefinic hydrocarbons and derived from a mineral'source with a nitrosyl halide and an aqueous solution of a water-soluble sulfite, the. improvement which comprises removing chromogenetic constituents of an olefin-containing hydrocarbon mixture of the aforesaid type composed mainly of hydrocarbons containing 14 to 23 carbon atoms, by extracting one part by weight of said hydrocarbon mixture with 0.5 to 6 parts by weight of an extracting agent which is incompletely miscible with said hydrocarbon mixture, which has greater dissolving power for .the :oxygen containing, sulfur-containing, nitrogen-containing and aromatic constituents of cracked petroleum than for the paraflins and cycloparafiins of cracked petroleum, and which is a memberof the group consisting of methyl lactate, methyl formate, diethylene glycol, turiuryl alcohol, ethanolamine, diethanolamine, ethylene chlorohydrin, beta-beta-dichlordiethyl ether, ethylene glycol monomethyl ether, furfural, phenol, cresol, nitro-methane, nitro-benzene, morpholine, pyridine, methylamine, ethylene diamine and sulfur dioxide, under temperature and pressure conditions at which the extracting agent is in the liquid phase, separating the solventextract phase from the rafllnate phase, and reacting olefins contained in the raiilnate phase with the nitrosating agent.

3.iIn a process for preparing surface-active agents by successively reacting a hydrocarbon mixture containing oleiinic hydrocarbons and derived from a mineral source with a nitrosyl halide and an aqueous solution of a water-soluble sulfite, the improvement which comprises removing chromogenetic constituents of an olefin-containing hydrocarbon mixture of the aforesaid type composed mainly of hydrocarbons containing 14 to 23 carbon atoms, by extracting 1 part by weight of said hydrocarbon mixture with 0.5 to 6 parts by weight of furfural at to 70 C., separating the solvent-extract phase from the raflinate phase, and reacting olefins contained in the raflinate phase with the nitrosyl halide.

4. In a process for preparing surface-active agents by successively reacting a hydrocarbon mixture containing oleflnlc hydrocarbons and derived from a mineral source with a nitrosyl halide and an aqueous solution of a water-soluble sulfite, the improvement which comprises removing chromogenetic constituents of an olefin-containing hydrocarbon mixture of the aforesaid type composed mainly of hydrocarbon containing14 to 23 carbon atoms, by extracting 1 part by weight of said hydrocarbon mixture with 0.5 to 6 parts by weight of liquid sulfur dioxide at a temperature below 50 C. under superatmospheric pressure, separating the solvent-extract phase from the raflinate phase, and reacting olefins contained in the raflinate phase with the nitrosyl halide.

5. In a process for preparing surface-active agents by successively reacting a petroleum fraction containing olefinic hydrocarbons with nitrosyl chloride and an aqueous solution 01 a watersoluble sulfite, the improvement which comprises removing chromogenetic constituents of an olefinconta ining petroleum fraction composed mainly of hydrocarbons containing 14 to 23 carbon atoms, by extracting said petroleum fraction with l6 extract phase from the rafllna'te phase, and reacting olefins contained in the railinate phase with nitrosyl chloride.

6. In a process for preparing surface-active agents by successively reacting a hydrocarbon mixture containing olefinic hydrocarbons and derived from a mineral source with a nitrosyl halide and an aqueous solution of a water-soluble sulilte, the improvement which comprises removing chromogenetic constituents of an olefin-contain ing hydrocarbon mixture of the aforesaid type composed mainly of hydrocarbons containing 14 to 23 carbon atoms, by extracting one part by weight of said hydrocarbon mixture with 0.5 to 6 parts by weight of ethylene glycol monomethyl ether at 0 to 70 C., separating the solventextract phase from the rafllnate phase, and reacting olefins contained in the railinate phase with the nitrosyl halide.

7. In a process for preparing surface-active agents by successively reacting a petroleum fraction containing oleflnic hydrocarbons with nitrosyl chloride and an aqueous solution of a 2.5 to 5 parts by weight of substantially moisturefree Iurfural, per part by weight of the petroleum fraction, at 25 to 50 0., separating the solventwater-soluble sulfite, the improvement which comprisesremoving chromogenetic constituents of an olefin-containing petroleum fraction composed mainly of hydrocarbons containing 14 to 23 carbon atoms, by extracting said petroleum fraction with 2.5 to 5 parts by weight of substantially moisture-free ethylene glycol monomethyl ether, per part by weight of the petroleumfraction, at 25 to 50 C., separating the solvent-extract phase from the rafllnate phase, and reacting olefins contained in the rafiinate phase with nitrosyl chlo r de.

' LELAND JAMES BECKHAM.

WILLIAM ALFRED FESSLER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Certificate of Correction Patent No. 2,447,308. r Y

LELAND JAMES BECKHAM ET AL. It is hereby certified that error appears in the printed specification of the above numbered patent requiring. correction as follows: Column 13, line 9, for Patent N 0. 2,370,513 read Patent No. 2,570,518 and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Oflice.

Signed and sealed this 26th day of October, A. D. 1948.

August 17, 1948.

THOMAS F. MURPHY,

Assistant Commissioner of Patents. 

